Fluid pressure mechanism



Sept. 29, 1942.

' w. A. EATON FLUID PRESSURE MECHANISM Filed July 21, 1941 wig redAEJ as 71.0 awf Patented Sept. 29, 1942 FLUID PRESSURE MECHANISM Wilfred A. Eaton, Elyria, Ohio, 'assign'or 'to Bendix-Westinghouse Automotive Air Brake Company, Elyria, Ohio, a corporation of Delaware Application July 21, 1941, Serial No. 403,409

14 Claims. (Cl. 303-88) This invention relates to fluid pressure systems and more particularly to a mechanism for automatically exhausting liquid condensate from a compressed air system.-

In the use of compressed air systems heretofore, it has been found that, during operation, a certain amount of liquid condensate is separated from the pressure fluid and usually 'flnds its way to the lowest point in the system. In mild weather, the existence of such condensate offers no serious difficulties and may be carried through the system and exhausted therefrom. However, in severe cold weather, such condensate is apt to freeze and thereby obstruct the proper flow of fluid pressure to effect the desired functions of the system as well aspreventing normal operation of automatic liquid condensate dis-charging systems. Various devices have been resorted to heretofore in an attempt to either prevent freezing of such condensate or to periodically drain the same from the system. However, these prior arrangements have possessed certain disadvantages in that they utilize auxiliary devices for preventing the condensate from freezing or for discharging the condensate from the system.

One of the objects of the present invention is to provide a fluid pressure system constituted in such a manner to avoid the above mentioned difflculties.

A further object is to provide a fluid pressure system arranged so as to automatically and \periodically eliminate the condensate during all weather conditions without any thought or attention on the part of the operator.

A still further object is to provide, in a system of the above character, a novel arrangement wherein fluid pressure, at substantially high temperature when delivered from a fluid compressor, is utilized for maintaining the condensate accumulated in the system above freezing temperatures.

A further object is to provide a novel arrangement of the above type which will be relatively inexpensive and which will require no attention on the part of the operator.

Other objects and novel features of the invention will appear more fully hereinafter from a consideration of the following detailed description when taken in consideration with the ac- I companying drawing illustrating one embodiment of the invention. It is to be expressly understood, however, that the drawing is utilized for the purpose of illustration only and is not designed as a definition or the limits of the invention, refer- 55 ence being had for this purpose to the amended claims;

In the drawing, a diagrammatic view, partly in section, is shown disclosing one embodiment of the present invention.

Referring more particularly to the construction illustrated in the drawing, there is disclosed therein, a fluid pressure system constructed according to the principles of the present invention including a fluid compressor 3, driven by-the internal combustion engine of the vehicle not shown, for supplying fluid pressure controlled by the usual unloader of governing mechanism 4, to a plurality of reservoirs 5 and fi'through conduit 1. Fluid pressure stored in the reservoir 6 may be utilized for operating various fluid pressure mechanisms of the vehicle, such as brake actuators for example, not shown, conduit 8 being provided for conducting fluid pressure to such mechanisms. Although only two reservoirs have been shown in the drawing, it is to be expressly understood that additional reservoirs may be included in series relationship with the reservoirs shown.

The reservoirs are so connected that they are serially supplied with fluid pressure from the compressor 3 and a portion of such connection is adapted to be utilized for conducting liquid :condensate which may accumulate in the reservoir 6 to the reservoir 5 upon a reduction in pressure in the latter with respect to the reservoir 5. As shown in the drawing the connection includes conduit 9 which conducts fluid pressure from the reservoir 5 to the reservoir 6; casing l5, secured to the latter reservoir, and having aport I I therein which is in fluid communication with the conduit 9; and a conduit l2, threadedly secured to the casing I0 so as to be in fluid communication with port I l. The conduit 12 is mounted to extend downwardly into the reservoir 6 and terminates near the bottom thereof in such a manner that the lower end thereof will be immersed in the liquid condensate that may accumulate in the reservoir. It will be apparent that with such construction, upon a reduction of the pressure of the fluid in the reservoir 5 with respect to the reservoir 6, pressure of the fluid in the reservoirs will tend to equalize to thus cause a flow of fluid pressure from the reservoir 6 to the reservoir 5 forcing the accumulated liquid condensate in reservoir B to the reservoir 5, through conduit [2, port H and conduit 9.

Means responsive to a predetermined pressure of the fluid in reservoir 5 are provided for controlling the exhaust to atmosphere of the liquid condensate accumulated in the reservoir and, as

shown, such means comprises a valve device |3 which includes casing members I4 and I5 suitably secured together with a pressure responsive diaphragm l6 clamped therebetween to form chambers I1 and I8. The chamber I! is in communication with the reservoir 5 through a port l9 and a conduit 28 which extends downwardly into the reservoir and terminates adjacent to the bottom thereof to contact the liquid condensate which may be accumulated therein. The chamber I! also may communicate with the atmosphere through port 2| and a conduit 22. However, the latter communication is normally closed by a valve member 23, secured to the diaphragm 6, and normally maintained in such position as to close the port 2|, by means of a spring 24 positioned in the chamber I8. 25 is provided for varying the tension of thespring 24 thus controlling the degree of pressure required in the chamber H to move the valve member 23 away from its Seat to open the atmospheric connection. It will be apparent from the foregoing description that when suflicientpressure is built up in reservoir 5 to operate the valve l3 in the above manner the condensate accumulated in the bottom of this reservoir will be forced upwardly through the conduit and hence to atmosphere, through the port 2| and conduit 22.

When fluid pressure systems of the foregoing character are operated during adverse weather conditions, the liquid condensate accumulated in the reservoirs of the system may freeze and thus prevent the automatic dischar e of such condensate to the'atmosphere as well as preventing the normal flow of fluid pressure through the system. As heretofore stated, the present invention provides means for utilizing the warm fluid pressure delivered from the compressor in such a manner to overcome the disadvantageous effects enumerated above. 1 As shown in the drawing, such means includes a manifold 26 cast in the casing mamber M of the valve l3 in such a manner that the warm fluid pressure delivered from the compressor 4 is circulated around the portions in valve 13 with which the liquid condensate contacts, namely, chamber I1 and the ports I9 and 2|, in order to maintain such portions above freezing temperatures. Such means also includes conduit 28 mounted concentrically about the conduit 20 and extended downwardly toward the bottom of the reservoir so that warm fluid pressure from the manifold 26 will be supplied to the reservoir through theconduit 28 by way of ports 21. The flow of warm fluid pressure to the reservoir 5 in the ,above manner not only maintains the conduit 20 above freezing temperatures, but also prevents the accumulated liquid condensate in the reservoir adjacent the lower end of conduit 20 from .freezing. It is to be noted that the conduit 28 does not extend downwardly into the reservoir as far as the lower end of the conduit 20, such construction being provided toprevent the liquid condensate from contacting the lower end of the conduit 28. If such contact was allowed, the liquid condensate might freeze during extreme weather conditions when no fluid pressure was delivered from the compressor to thus obstruct the flow of fluid pressure through thelatter conduit.

In the event that the accumulated liquid condensate in reservoir 6 freezes due to adverse weather conditions and thus obstructs the normal flow of fluid pressure through the conduit l2, the flowof fluid pressure to the latter reservoirs and the discharge of liquid condensate therefrom Adjustable member 7 would be prevented. However, means are provided by the present invention for automatically conducting a supply of warm fluid pressure from the reservoir 5 to the reservoir 6 through an auxiliary passage when the normal communication to the latter reservoir is obstructed. Such means operates to effect a rise in the temperature of conduit |2 as well as the condensate near the end thereof whereby the frozen condensate is reduced to liquid form to thus allow normal communication between the reservoirs. As shown, the above mentioned means includes a conduit 29 positioned concentrically about the conduit l2, extending downwardly toward the bottom of the reservoir and terminating a substantial distance above the lowermost end of the conduit I2, for a purpose similar to that outlined heretofore with reference to the conduits 2!] and 28. A port 30 in the casing I!) is provided for forming a fluid connection between conduit 29 and the port II. This connection, however, is normally closed by ball valve 3| which is maintained against the upper end of the port H by means of a spring 32, the foregoing elements being enclosed in a casing 33 secured to the casing l0. It will be evident that upon an increase of fluid pressure in conduit l2, due to frozen condensate therein, valve 3| will be moved upwardly against the spring 32 to open the fluid connection between conduits 9 and 29. Warm fluid pressure from the reservoir 5 will then be supplied to th reservoir 6 through the conduit 29. The latter conduit will then conduct the warm fluid pressure over the outer surface of conduit l2 to raise the temperature thereof, and will discharge the fluid pressure into the reservoir adjacent the bottom thereof against the frozen condensate to effectively reduce the latter to liquid form.

In operation of the novel fluid pressure system discussed heretofore, fluid, pressure at substantially high temperatures is delivered from the compressor 3 through conduit 1 to manifold 26 and hence into the reservoir 5 through the conduit 28. Fluid pressure from reservoir 5 is conducted to the reservoir 6 through conduits 9 and I2, and pressure of the fluid in both reservoirs builds up at a substantially equal rate. It will be apparent that the'fiow of warm fluid pressure directly from the compressor into the manifold 26 will maintain casing l4 above freezing temperautres and. also, the introduction of such fluid pressure into the reservoir through conduit 28 will maintain conduit 28 as well as the liquid condensate accumulated in the reservoir above freezing temperatures.

Further operation of the compressor 4 will cause a substantially equal increase of the pressure of the fluid in the reservoirs 5 and 6, and when pressure of the fluid in reservoir 5 reaches a value to operate the valve I3, the valve member 23 will be moved away from its seat to thus open the atmospheric connection with the reservoir 5 through conduit 20, chamber port 2| and conduit 22. When such atmospheric connection is made, pressure of the fluid in reservoir 5 will force the liquid condensate accumulated in the reservoir through such connection to atmosphere. When the compressor is operated at a substantially high speed the pressure of the fluid in reservoirs 5 and 6 will continue to build up at a substantially equal rate, although the valve |3 may be open. This latter action would occur because the rate of flow of fluid pressure to the reservoir 5 through conduit 28 would be greater than the rate of flow of liquid condensate from the reservoir to theatmosphere through the conduit 20.- However, when the rateof flow of fluid pressure into the reservoir 5 through conduit 28 drops'below the rate of flow through the atmospheric connection, due to a drop in the speed of the compressor 3'or due to operation of the unloading device 4,- a reduction of pressure of the fluid in reservoirs will occur. Such reduction in pressure will cause a flow of fluid pressure from reservoir 6 to reservoir 5 and the accumulated liquid condensate in the former reservoir would be conducted by such action to reservoir 5 through'conduit l2, port H and conduit 9, and from reservoir 5 to atmosphere in a manner fully outlined heretofore.

When operating under severe weather conditions which may cause the liquid condensate accumulated in the reservoir 6 to drop below freezing temperatures it ispossible for the same to freeze about the lower end of conduit l2' and thus obstruct the normal fluid communication between the reservoirs. In the event that such action occurs an increase of the pressure of the fluid in conduit I2 would result, causing the ball valve 3! to move upwardly against the light spring 32 to open the auxiliary communication to reservoir 6 through port 30 and conduit 29. The flow of warm fluid pressure through conduit 29 will increase the temperature of conduit I2 to a value above freezing and thus reduce any condensate that may have frozen therein to liquid form. Such introduction of warm fluid pressure will also tend to reduce the frozen condensate near the lower end of conduits 29 and I2 to liquid form so that normal communication between the reservoirs through conduit [2 will be restored.

There has then been provided by the present invention a novel and emciently operable fluid pressure system embodying relatively simple means for relieving the system of liquid condensate notwithstanding the severity of the weather which, during severe cold weather, would freeze and adversely affect the various valves and other devices necessary for operating vehicle controlling fluid pressure-operated devices. The use of the plurality of reservoirs arranged in series insures a relatively complete condensation of the liquid entrained in the fluid pressure system, while the connections between these reservoirs, the use of the pressure-responsive valve devices disclosed, and the utilization of the warm fluid pressure delivered by the compressor for maintaining the liquid condensate, as well as certain parts of the system above freezing temperatures secures an automatic and efficiently operable exhausting of the liquid condensate.

While one embodiment of the invention has been disclosed and described herein, it will be understood that various changes in the component parts of the structures may be resorted to without departing from the spirit of the invention, as well understood by those skilled in the art. Reference will, therefore, be had to the appended claims for a definition of the limits of the invention.

What is claimed is:

1. In combination with a reservoir for receiving fluid pressure, means for discharging accumulated condensate from said reservoir, and means for supp-lying fluid pressure to said reservoir in heat exchange relation with the first named means.

'2. In combination with a reservoir for receiving fluid pressure, a fluid compressor, means for exhausting condensate accumulated in said reservoir to atmosphere, and means for supplying warm fluid pressure from said compressor to said reservoir in heat exchangerelation with the first namedmeans.

3. In combination with a reservoir for receiving fluid pressure, means including a conduit extending into and terminating adjacent the bottom of said reservoir for discharging accumulated'condensate therefrom, and means for conducting fluid pressure to said reservoir in heat exchange'relation with said conduit.

4. In combination with a reservoir for receiving fluid pressure, means forming a connection for discharging condensate accumulated in said reservoir to atmosphere, means responsive to the pressure of the fluid in said reservoir for controlling the opening and closing of said connection, and means for conducting fluid pressure supplied to said reservoir in heat exchange relation with said connection for maintaining the latter above freezing temperature.

5. In combination with a reservoir for receiving fluid pressure and a fluid'compressor, means forming a connection for discharging condensate accumulated in said reservoir to atmosphere, means responsive to a predetermined pressure of the fluid in said reservoir for controlling the opening and closing of said connection, and means for supplying warm fluid pressure for said compressor to said reservoir in heat exchange relation with the first named means.

6. In a fluid pressure system having a reservoir for receiving fluid pressure, means for discharging accumulated condensate from said reservoir, and last named means icludinga conduit extending into and terminating adjacent the bottom of the reservoir, and means for supplying fluid pressure to said reservoir in heat exchange relation with said conduit, the last named means including a second conduit mounted concentrically about the first conduit, extending into and terminating near the bottom of said reservoir.

'7. In combination with a reservoir for receiving fluid pressure, means forming a connection between said reservoir and the atmosphere for conducting condensate accumulated in said reservoir to the atmosphere, valvular means responsive to a predetermined pressure of the fluid in said reservoir for opening said connection, and means'for introducing fluid pressure to said reservoir in heat exchange relation with said first named means and said valvular means.

8. In combination with a fluid pressure receiving system having a reservoir and a source of warm fluid pressure, means for connecting said source and said reservoir, said means including a first conduit extending into and terminating near the bottom of said reservoir, a second conduit positioned in said reservoir and mounted concentrically about said first conduit, and means for conducting Warm fluid pressure from said source to said second conduit when communication through said first conduit is obstructed by frozen condensate to introduce warm fluid pressure to said reservoir in heat exchange relation with said first conduit.

9. In combination with a fluid pressure system having a plurality of reservoirs, means for serially supplying fluid pressure from one reservoir to an adjacent reservoir and for serially conducting accumulated condensate from said adjacent reservoir to said one reservoir upon a reduction of pressure in the latter with respect to said adjacent reservoir, means for discharging accumulated condensate from said one reservoir, and means for supplying fluid pressure to said one reservoir in heat exchange relation with the last named means to maintain the latter above freezing temperatures.

10. In combination with a fluid pressure system having a plurality of reservoirs, means for serially supplying fluid pressure from one reservoir to another and for serially conducting accumulated condensate from said another reservoir to said one reservoir upon a reduction of pressure in the latter with respect to said another reservoir, means for discharging accumulated condensate from said one reservoir, means for introducing fluid pressure to said one reservoir in heat exchange relation with the last named means, and means for introducing fluid pressure to said another reservoir in heat exchange relation with said first named means when communication through said first named means is obstructed by frozen condensate.

11. In combination with a fluid pressure system having first and second reservoirs and a fluid compressor, means for supplying fluid pressure from said first to said second reservoirs and for conducting accumulated condensate from said second to said first reservoirs, said means including a conduit extending into said second reservoir and terminating near the bottom thereof, means for discharging the condensate accumulated in said first reservoir, means for supplying warm fluid pressure from said compressor to said first reservoir in heat exchange relation with the last named means, and means for introducing fluid pressure from the first reservoir to said second reservoir in heat exchange relation with the extending portion of said conduit' when communication therethrough is obstructed by frozen condensate.

12. In a fluid pressure receiving system having first and second reservoirs, means for serially supplying fluid pressure from said first to said second reservoirs and for serially conducting condensate accumulated in said second to said first reservoirs upon a reduction in pressure in the latter with respect to said second reservoir, the last named means including a conduit extending into and terminating adjacent the bottom of said second reservoir, an atmospheric connection associated with said first reservoir including a second conduit extending into and terminating contained therein, means for introducing fluid pressure to said first reservoir in heat exchange relation with said second conduit, and means for introducing the fluid supplied'to said second reservoir in heat exchange relation with the extending portion of the first named conduit when com.- munication through said conduit is obstructed by frozen condensate.

13. In a fluid pressure system having a plurality of reservoirs, means including a first conduit extending into and terminating near the bottom [of one of said reservoirs for supplying fluid pressure thereto, means for supplying fluid pressure from said one reservoir to another reservoir, a second conduit positioned in said another reservoir having one end connected to the last named means and the other end thereof terminating adjacent the bottom of said another reservoir for conducting accumulated condensate in said another reservoir to said one reservoir upon a reduction of pressure in the latter with respect to said another reservoir, means for exhausting accumulated condensate from said one reservoir and for effecting a reduction of pressure of the fluid contained therein, the last named means including a third conduit positioned concentrically with respect to said first conduit and in heat exchange relation with the fluid pressure supplied to said first conduit, and means for introducing fluid pressure to said another reservoir when communication through said second conduit is obstructed by frozen condensate, the last named means including a fourth conduit positioned concentrically about said second conduit for introducing fluid pressure to said another reservoir in heat exchange relation with said second conduit.

14. In a fluid pressure system having first and second reservoirs and a fluid compressor, a conduit for supplying fluid pressure from said first reservoir to said second reservoir, said conduit having one end connected to said one reservoir and the other end thereof terminating within said second reservoir adjacent the bottom thereof for conducting condensate collected in said second to said first reservoirs upon a reduction of pressure in the latter With respect to said second reservoir, means for discharging the condensate accumulated in said first reservoir and for effecting a reduction of pressure of the fluid therein, means for supplying warm fluid pressure from said compressor to said first reservoir in heat exchange relation with the last named means, and means for introducing the fluid pressure to said second reservoir in heat exchange relation with that portion of said conduit extending into said second reservoir when the end of said conduit is obstructed by frozen condensate.

WlLFRED A. EATON. 

